J/A+A/558/A6 Microwave spectrum of 2-pentynenitrile (C2H5CCCN) (Carles+, 2013)
Rotational spectrum of ethyl cyanoacetylene (C2H5CCCN), a compound of potential
astrochemical interest.
Carles S., Mollendal H., Guillemin J.-C.
<Astron. Astrophys. 558, A6 (2013)>
=2013A&A...558A...6C 2013A&A...558A...6C
ADC_Keywords: Atomic physics ; Interstellar medium
Keywords: methods: data analysis - surveys - molecular data -
methods: analytical - techniques: spectroscopic
Abstract:
New radiotelescopes, such as the very sensitive ALMA, will enable the
detection of interstellar molecules in much lower concentrations than
previously possible. A successful identification of an interstellar
molecule requires that laboratory microwave and millimeter-wave
spectra are investigated. Several cyanopolyynes and
alkynylcarbonitriles have already been detected in the interstellar
medium (ISM). Cyanoacetylene (HCCCN) is abundant in the ISM and its
methyl derivative, 2-butynenitrile (CH3CCCN), is also present. The
next derivative, ethyl cyanoacetylene, (2-pentynenitrile C2H5CCCN)
may also be present in interstellar space.
We report the rotational spectrum of the ethyl cyanoacetylene
(C2H5CCCN). This is hoped to facilitate identifying gaseous
ethyl cyanoacetylene in the ISM.
Description:
The C2H5CCCN molecule is a candidate for a possible interstellar
detection. We have recorded the microwave spectra of this molecule
between 13 and 116GHz. We have assigned 342 transitions of the
vibrational ground state summerized in the table6. Sorensen's program
ROTFIT was used to least-squares fit the lines employing Watson's
S-reduction and Ir-representation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 63 342 Rotational spectrum of C2H5CCCN
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See also:
J/A+A/466/255 : Isotopic ethyl cyanide (Demyk+, 2007)
J/A+A/493/565 : Deuterated and 15N ethyl cyanides (Margules+, 2009)
J/ApJ/714/476 : Complete spectrum of ethyl cyanide (Fortman+, 2010)
J/ApJS/184/133 : New ground-state measurements of ethyl cyanide (Brauer+, 2009)
J/A+A/543/A135 : New analysis of 13C-CH3CH2CN up to 1THz (Richard+, 2012)
Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ju [3/43] Transition J of the upper level (1)
4- 5 I2 --- K-1u [0/17] Transition K-1 of the upper level
7- 8 I2 --- K+1u [2/36] Transition K+1 of the upper level
10- 11 I2 --- Jl [4/44] Transition J of the lower level
13- 14 I2 --- K-1l [0/17] Transition K-1 of the lower level
16- 17 I2 --- K+1l [3/37] Transition K+1 of the lower level
19- 27 F9.2 MHz Freq [10402/115955] Observed frequency
29- 34 F6.3 MHz O-C [-0.4/0.3] Observed minus calculated residuals
36- 39 F4.2 MHz Weight Estimated uncertainties of the observed
frequencies (2)
41- 45 F5.2 --- t Student's t-test
47- 53 F7.3 MHz CorrT Total distortion corrections from quartic and
sextic (if included) centrifugal distortion
constants
55- 63 E9.4 MHz CorrH Higher distortion corrections, contribution
from sextic centrifugal distortion constants
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Note (2): Each transition is weighted according to the inverse square of
its estimated uncertainty.
Note (1): rms deviation: 1.1597
Rotational constants (MHz) and κ:
21750 1344.8187 1285.4798 -0.994201
± 21 0.0030 0.0029 0.000006
Inertial constants and defect (uÅ2):
23.236 375.79717 393.14433 -5.889
± 0.022 0.00085 0.00089 0.023
Quartic distortion constants:
0.162867 -13.6967 0 0 0
± 0.00068 0.0090 fixed fixed fixed
Standard distortion constants (kHz):
54.13540 -0.651467 -0.651467 26.74197 -0.651467 26.74197
Sextic and higher distortion constants:
0.0002868 -0.008587 -0.5276 0 0
± 0.00020 0.0032 0.039 fixed fixed
± fixed fixed
Significant Digits and Correlation Matrix:
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5 0.206 -0.283 -0.391 0.142 -0.116 -0.325 0.286
8 -0.889 0.167 0.179 0.109 0.089 0.062
8 0.135 0.031 0.084 0.063 -0.019
6 -0.312 0.849 0.074 -0.267
6 -0.384 0.289 0.559
4 -0.427 0.060
4 -0.593
4
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Acknowledgements:
Sophie Carles, sophie.carles(at)univ-rennes1.fr
(End) Sophie Carles [CTCC, Norway], Patricia Vannier [CDS] 10-Jun-2013